I'm getting ready to sell my Voigtlander 125/2.5 Canon mount (mint, all accessories, boxed) and need to describe what's on an internal element. It was like this when I bought the lens (used) several years ago and hasn't changed. I'll withhold my opinion because I really don't know what it is and don't want to influence the discussion. I'd also like to know how much this affects the price.

Follow the blue arrows:

Delamination? Doesn't really look like fungus.

Looks like cells dividing.

I"d just call it spots on one of the internal elements. It will affect the value some, but probably won't have any measurable affect on image quality.

Agree, it doesn't look like fungus, but IMHO, delamination is just as serious. I personally have no clue what else it could be nor how it affects the price. Great that it hasn't changed in your years of use. Did the original owner live some place with extreme temperatures?

Looks like it got wet inside and then left a residue after drying. Saltwater, beer, or something besides clean water

Thanks for the comments so far. The lens was purchased new in Korea. It's tough to get a picture of it but is easy to see when I rotate the lens around in the light. It doesn't appear that anything is coming off the element because if it were, there would be little pieces of "coating dust" all over the place, no? It looks like something is on the element. Highly unlikely that it's beer, but you never know!

Agreed with pdmphoto.

Doesn't look like separation, that always starts at the edges, and looks much different anyway.

I have no idea what that could be... If I blur my eyes a bit it does look like Hite froth though....

Gary Clennan wrote:
I have no idea what that could be... If I blur my eyes a bit it does look like Hite froth though....

Haha.. An unfortunate beverage if ever there was one.

pdmphoto wrote:
Looks like it got wet inside and then left a residue after drying. Saltwater, beer, or something besides clean water

+1, condensation, residue, something on those lines. It doesn't look like fungus.

I think that 2 elements glued together are getting separated.

send it in?

My assertion, FWIW: they're water spots.

This lens was soaked at some point, either a dunk or a really heavy condensation that formed drips on the internal surface. As the drips evaporated their contracting margins drew salts and other soluble contaminants, that were probably already on the surface, toward the centre of these isolated oases, until eventually the contamination piled up deep enough to be seen when the surface finally dried.

You can produce a similar effect by spattering a little distilled water on an apparently clean (but not freshly cleaned) protection filter and allowing it to dry undisturbed.

/Acme

The spots are isolated on the surface of just one side of one element as far as I can tell, and that element seems to be right in the middle of the lens. Could it be residue or something that was part of the manufacturing process? I don't see how these spots could have gotten there, given their isolation, after the lens was put together. But what do I know, eh? The exterior of the lens seems to be as good as new minus a few scuffs here and there from normal usage. And functionally, it's perfect. Never had problems with the electronics, focus ring, or whatever.

My first thought was water spots.
Anyways, here's a diagram, it may help you figure out which element the marks are on.

pdmphoto wrote:
Looks like it got wet inside and then left a residue after drying. Saltwater, beer, or something besides clean water

+1

Also, as Ed mentioned, it doesn't look like delamination.

pdmphoto wrote:
Looks like it got wet inside and then left a residue after drying. Saltwater, beer, or something besides clean water

Yup!

It's not any kind of "delimitation" I've ever seen nor does it look like fungus. It for sure looks like dried up liquid. Either it's dirty in there and some humidity bunched up to form droplets that later dried up or it's like pdmphoto is saying here.